Cut rubberised stranded wire

ABSTRACT

A laser cut rubberized wire, in particular serving as a reinforcing insert for a tire, comprising steel cord wire elements enclosed in a rubber coating, said wire elements having laser cut ends which are rounded or fused.

United States Patent v 1191 Kogert 1 Nov. 6, 1973 1 CUT RUBBERISEDSTRANDED WIRE 331/945; 250/495; 264/145, 160

[76] inventor: Herbert Kogert,Huttellbergstrasse 7a, 1140 Vienna,Austria [561 References CM UNITED STATES PATENTS [22] 1971 2,732,8811/1956 Anderle 156/88 [21] Appl. No.: 207,078 3,597,578 8/1971 Letchwonh219 121 Related [15' Apphcanon Data Primary Examiner-William A. Powell[62] D1visi0n of Ser. No. 881,235, Dec. 1, 1969. Atmmey wemer Kleeman[30] Foreign Application Priority Data [57] ABSTRACT Dec. 5, 1968Austria A 11890/68 A laser cut rubberized wire, in particular serving asa 52 us. c1 161/144, 156/270, 156/510, :12:2 1 161/175 t h v'n 1 r utnds whi h 1' rounded or 1511 1111.01 B326 5/08, B32b 25/02 2;; a g c e ca e [58] Field of Search 140/139, 140;

3 Claims, 5 Drawing Figures PATENIEnNuv 6 i915 3770.561

I SHEET 2 UF 2 Fig .4

CUT RUBBERISED STRANDED WIRE CROSS-REFERENCE TO RELATED CASE The presentapplication is a divisional of my commonly assigned, co-pending US. Pat.application, Ser. No. 881,235, filed Dec. 1, 1969 and entitled PRO- CESSAND APPARATUS FOR CUTTING RUBBER- ISED STRANDED WIRE.

BACKGROUND OF THE INVENTION The present invention deals with laser cutrubberized wire, in particular serving as a reinforcing insert for themanufacture of tires, wherein said laser cut rubberized wire isfabricated according to the process and apparatus disclosed in mypreviously mentioned US. Pat. ap plication, Ser. No. 881,235.

Such reinforcing inserts have heretofore been cut from a length ofrubberized wire through the use of mechanical cutting devices, such ashammer shears or rotary blade cutters. Such cutting devices, however,possess the disadvantage, in particular where steel cord inserts areconcerned, that during the cutting action the strands tend to fan out,therefore their ends constitute a danger point in the finished tire. Asource of internal damage to. the tire structure is often formed due tothe fact that the wire strand ends cut into the rubber structure andform cracks which are then enlarged by the flexing action of the tireduring usage. Furthermore, with mechanical cutting operations thesurface bonding layer of the steel cords, provided for the purpose ofimproving the adherence to the rubber, is broken at the cut, againincreasing the danger of subsequent damage to the finished tire duringuse.

The viability of a laser, and in particular a gas laser in the field oftire manufacture, has heretofore been regarded as unprofitable,considered by those skilled in the art to be both uneconomical andunsuitable. The former was based upon the expense involved and thelatter in view of the general opinion that such widely differingmaterials as rubber and metal could not be simultaneously cut by asingle laser beam because the rubber would burn away from the metal hadbeen properly cut.

SUMMARY OF THE INVENTION In my previously mentioned co-pending UnitedStates application, there was disclosed both the process and apparatusfor cutting rubberized wire, by means of which the cutting operation wascarried out by a laser beam moved along a desired line of cut, andpreferably employing a gas laser for projecting the laser beam used tocut the rubberized wire.

It has been surprisingly found that the cutting of such dissimilarmaterials as rubber and metal is possible with laser energy and may beeffected very efficiently by using a 250 Watt CO gas laser. Microscopicexamination of the cut surfaces of theindividual wires cut by the laserbeam shows that there are no sharp edges, and the majority of such wireends are in fact rounded-off by a melting process.

The action of the laser beam does not merely cut the stranded steelcords, but these are melted at the cutting zone, so that instead oftheir being present the sharp edges which are formed during conventionalcutting operations, the ends are actually rounded-off, thussubstantially eliminating the danger of any cutting action within afinished tire during use.

Hence, from what has been stated above it is a primary objective of thepresent invention to provide an improved article of manufacture, namelya laser cut rubberized wire, in particular serving as a reinforcinginsert for a tire, consisting of wire elements enclosed in a rubbercoating, these wire elements having laser cut ends which are devoid ofany sharp edges, and in particular wherein such cut ends are rounded orfused.

Furthermore, it has been found that a modification of the surface takesplace in the zone of the cut. This provides for improved bondingproperties, particularly if the cutting zone has been cooled by acooling device, since such prevents destruction of the rubber coating inthe area adjacent the cut.

In order to remove any danger of the rubber igniting, at least one jetof a shielding gas is directed over the cutting zone. For example, theshielding gas may be nitrogen, carbon dioxide or a rare gas. In order tokeep the zone of the cut and its environment free of decompositionproducts, it is convenient to provide an appropriate suction device atthe zone of the cut as will be explained more fully hereinafter.

Several layers can be simultaneously cut if they are held firmlytogether. Otherwise, any combustion gases tend to glow between thelayers and lead to blackening at the edges. The cooling equipmentemployed in the practice of the invention serves to exert a pressure onindividual layers, if more than one layer is inserted into the cuttingdevice, so that they remain in contact with one another, and henceovercome this problem.

BRIEF DESCRIPTION OF THE DRAWING The invention will be better understoodand objects other than those set forth above, will become apparent whenconsideration is given to the following detailed description thereof.Such description makes reference to the annexed drawings wherein:

' FIG. 1 is a schematic illustration'of one exemplary embodiment ofequipment used in the practice of the invention;

FIG. 2 is a fragmentary plan view of the cutting area in the embodimentdepicted in FIG. 1;

FIG. 3 is a cross-sectional view of the cutting area of the exemplaryembodiment of FIG. 1;

FIG. 4 is an enlarged schematic view showing details of the laser cutrubberized wire produced in accordance with the teachings of thisinvention; and

FIG. 5 is an enlarged section of the laser cut rubberized wire of FIG.4, showing the cut rounded or fused wire end.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Describing now thedrawings, in FIG. I there is schematically depicted a preferredconstruction of apparatus for carrying out the teachings of theinvention, and such will be seen to embody a roller track 1 whichconveys a reinforced rubberized steel wire fabric 2 which is to be cutso as to pass below a high-energy laser device 3. Laser device 3 ismounted on transverse rails 4 so as to enable the laser device 3, whichis the source of the laser beam, to be moved along the required cuttingline by any suitable means which have not been particularly shown.

FIGS. 2 and 3 illustrate details of the arrangement at the cutting zonewherein four cooled bars 5 are provided, each such cooled bar extendingparallel to the cutting line, and two of the cooled bars being locatedabove the reinforced fabric or web 2 and two located below such fabricor web, with one such cutting bar disposed to each side of the cuttingline. Hence, the reinforced fabric or web 2 can be clamped between thecooled bars 5 prior to the cutting operation. The laser device 3 is thendriven along the rails 4 so that its beam 6, the cross-section of whichhas been indicated in FIG. 2, is directed between the upper pair ofcooling bars 5 onto the reinforced fabric or web 2. At the point ofimpact of the laser beam at the reinforced fabric or web 2 there isprovided a shielding gas flow by means of an upper jet 7 and a lower jet7', this gas flow is drawn-off by suction devices 8, one being locatedabove and the other below the reinforced web 2.

During some applications it may be more convenient to employ astationary laser device, the laser beams 6 being moved along the line ofcut by any appropriate optical deflecting system.

Finally, in FIGS. 4 and 5, there is schematically depicted on anenlarged scale for the purposes of showing details, a laser cutrubberized wire produced in accordance with the previously consideredmanufacturing techniques and by means of the equipment described above,and in particular serving as a reinforcing insert for a tire. It will beseen that this laser cut rubberized wire comprises wire elements 20,typically steel cord wire elements, enclosed in a rubber casing orcoating 22. These wire elements 20 have laser cut ends 24 which aredevoid of any sharp cut edges, specifically have the material formingsuch wire elements rounded or fused, as shown. As previously explained,the absence of any such sharp edges, here possible when working withlaser energy, and as opposed to the heretofore employed mechanicalcutting operations, safeguards against any possible internal damage tothe tire structure which otherwise might arise if such sharp edges werepresent.

While there is shown and described present preferred embodiments of theinvention, it is to be distinctly understood that the invention is notlimited thereto but may be otherwise variously embodied and practicedwithin the scope of the following claims. ACCORD- INGLY,

What is claimed is l. A laser cut rubberized wire, in particular servingas a reinforcement insert for a tire, comprising wire elements enclosedin a rubber coating, said wire elements having laser cut ends devoid ofsharp edges.

2. A laser cut rubberized wire as defined in claim l, wherein said lasercut ends of said wire elements are rounded or fused.

3. A laser cut rubberized wire as defined in claim 2,

wherein said wire elements comprise steel cord.

2. A laser cut rubberized wire as defined in claim 1, wherein said lasercut ends of said wire elements are rounded or fused.
 3. A laser cutrubberized wire as defined in claim 2, wherein said wire elementscomprise steel cord.